Introduction to SQL

SQL stands for Structured Query Language which is used to access the database,manipulate the databases.

Structured query language(sql) is:

• The ANSI(American National Standard Institute)standard for operating relational databases.
• Efficient,easy to learn and use
• SQL is set of statements with which all programs and users access data in Microsoft sql database or in oracle database
• Querying data
• Inserting,updating,and deleting rows in a table
• Creating replacing,altering,and dropping objects
• Controlling access to the database and its objects
• Guaranteeing database consistency and integrity 

SQL unifies all of the preceding tasks in one consistent language and enables you to work with data at a logical level.

SQL commands:

SQL commands to interact with Relational Databases are CREATE,SELECT,INSERT,UPDATE,DELETE and DROP,commands can be classified into groups based on their nature.

DML - Data Manipulation Language:

Command	Description
SELECT	Retrieves certain records from one or more tables
INSERT	Creates a record
UPDATE	Modifies records
DELETE	Deletes records

DDL - Data Definition Language:

Command	Description
CREATE	Creates a new table, a view of a table, or other object in database
ALTER	Modifies an existing database object, such as a table.
DROP	Deletes an entire table, a view of a table or other object in the database.

DCL - Data Control Language:

Command	Description
GRANT	Gives a privilege to user
REVOKE	Takes back privileges granted from user